Timeline Comp

As both a personal project and a way to practice with Fusion, I am creating a short "timeline" style animation: sliding timeline ribbon on the bottom of the screen stops on a specific date, images appear above it. I've looked at a few tuts on the web, but it seems like I'm mostly puzzling things out for now.

I need a little help with an element I'm working on, its the timeline graphic element itself. I can't post images yet but think of a measuring ribbon that slides from right to left. I have the notches drawn on a polygon node piped into a small background node and then merged into screen-wide background node - the "Ribbon", with the Merge node having Edges>Wrap toggled to repeat the pattern. Finally the ribbon is placed on an Image Plane.

With a transform node placed before the Image Plane I can slide the notches on the ribbon, and with splines I can loop and smooth it. What I'm looking for is to control the speed of the sliding and/or make it stop and start again as needed. I'm haven't yet looked into expressions, but would the Time Speed node work? Not sure how to use it, though.